This invention relates to optical components and systems, and more particularly, to a modular, variably configurable retainer assembly for optical components.
Discrete optical components, such as couplers, isolators, combiners and wavelength division multiplexers (xe2x80x9cWDMsxe2x80x9d) are often interconnected to create optical circuits used to create a variety of functionalities provided by optical modules including multiplexers, demultiplexers, interleavers, deinterleavers, splitter arrays and the like. Optical fibers are typically utilized to provide the multiple optical paths among such components in the optical module. A number of mass fusion splices (that may include relatively high fiber counts) may also be necessary to implement the optical circuit which may include dozens of separate optical pathways. An optical module is typically embodied in a package that organizes and locates the optical components in an appropriate spatial relationship to effectuate the optical circuit while simultaneously affording physical protection to the optical components, fibers and splices. Such packages include various holders, trays or retainers that are populated with the optical components and mass fusion splices during the manufacturing buildup of the optical module. Typically, the holders, retainers, and trays (collectively referred to simply as xe2x80x9choldersxe2x80x9d) are then subsequently placed in an enclosure that houses and provides the exterior surfaces of the optical module. Optical cables or ribbons (i.e., pigtails) that may include connectors typically terminate the primary optical fibers and are then run outside the enclosure to provide access to the internal optical pathways.
Holders for optical components and splices in the prior art include those employing (alone or in various combinations) mechanical, adhesive, and magnetic retention solutions. Mechanical solutions include, for example, resilient foam to surround the optical components and splices, and press-fit and loose-fitting arrangements employing plastic retainers. Adhesives, such as glue and epoxy, have also been used to bond optical components and splices to the holder in the desired configuration. Optical components and splices may also be located in a holder using magnetic strips that are respectively affixed to the elements and holder. Some holder arrangements in the prior art, such as trays, require the use of a separate cover element to fully implement the required retention and/or protection of the optical components and splices.
Unfortunately, few prior art holders have proven to be entirely satisfactory. Disadvantages associated with such prior art holders include lack of precision in locating optical components and splices (foam, loose-fit), reduced physical protection (foam, loose fit), and reduced manufacturing flexibility in building up the optical module (adhesive), organizing the optical components and splices therein (adhesive), or configuring the holders themselves (all prior art solutions). Some holders in the prior art, for example, the adhesive and magnetic arrangements (and those requiring covers) also add undesirable extra manufacturing complexity, duration, and expense.
A variably configurable and modular retainer for various discrete optical components (such as passive optical elements and mass fusion splices) is provided by a substantially planar base having an optical component support surface. Complementary finger pairs extend upwardly from the base. Each finger is disposed in an opposing arrangement with the other finger in the finger pair and is provided with an inner and outer surface. The respective opposing inner surfaces (each having a slightly concave profile) define an optical component receiving area that is sized and shaped to accommodate an optical component or splice. Each finger pair is resilient and laterally biased with a normal bias such that the inner surfaces are urged laterally inwardly and being moveably outwardly for interlockingly engaging an optical component using a snap-fit. The optical component may be thereby retained substantially against the support surface of the base.
In an embodiment of the invention, side structures are disposed adjacent to the base that include one or more connective elements that form a selectively engagable interconnection with a complementary connective element on an adjacent retainer in a modular retainer assembly. The invention thus provides a modular retainer assembly (comprising a plurality of modular retainers) that may be arranged in a variably configurable planar array.
One portion of the connective element may comprise a male side structure including an resilient interlocking tab extending laterally from the male side structure. The other portion of the connective element may comprise an opposing female side structure that includes a mating slot arranged to mate with an interlocking tab of an adjacent retainer. A matching lug and recess, disposed respectively in the adjoining connective slot and tab, may be used to provide vertical registration of the side structures of the adjacent modular retainers to ensure substantial co-planarity of the assembled planar array. The interlocking tab and slot are slidably engaged along a vertical plane until the lug fits into the recess to thereby provide a snap-fit registration.
In another embodiment of the invention, the modular retainer assembly further includes an interconnector having first and second members each having complementary-shaped facing portions therewith. The first member is resilient and projects downward from the base. The second member is disposed on the base or side structures of the modular retainer. The complementary members thereby form a selectively engagable interconnection with an adjacent stacked modular retainer. The invention thus provides a stackable modular retainer that facilitates the assembly of the modular retainers into variably configurable columnar arrays.
The interconnector members may comprise a complementary hook and catch. The hook projects from the bottom of the retainer base with the opening of the hook projecting laterally inward with a normally inward bias. The catch is disposed on a top surface of the retainer with a lateral outward projection so as to receive the hook from a stacked modular retainer. The hook and catch are slidably engaged along a vertical plane as the adjacent modular retainer is placed to form the columnar stack. The hook deflects outwardly during the slidable engagement until it deflects past the lateral projection of the catch to thereby hold the catch in a snap-fit engagement.
The complementary finger pairs may be shaped to retain optical components with a substantially cylindrical cross sections or may be shaped to retain elements having an oval cross section such as mass fusion splices. The complementary finger pairs are arranged in a substantially rectangular and uniform grid having multiple rows and columns (in plan view) to thereby accommodate the retention of a plurality of optical components or splices in a spatial orientation that facilitates the interconnection of those elements to form an optical circuit. The placement of optical components and splices within the rows and columns of finger pairs may thus be variably configured according to the specific optical circuit being implemented, and additional retainers may be added in planar or columnar fashion to create a modular retainer matrix to implement other retention configurations as required by the application.
In various aspects of the invention, an injection-molded thermoplastic resin (such as polycarbonate) is used to form the modular retainer as a single unitary (i.e., monolithic) body. Optical fiber pathways may be molded into the top surface of the base to provide spaces within the modular retainer to accommodate the connective optical fibers used in an optical circuit. Modular retainers may be arranged to accommodate solely optical components (where the optical components are relatively small and consequently more may be accommodated by the modular retainer), or solely mass fusion splices (where the mass fusion splices are relatively large and consequently fewer may be accommodated by the modular retainer), or a combination of both optical components and mass fusion splices. However, in each such case, the modular retainers are sized to have a common footprint. In addition, the modular mass fusion splice retainer may be provided with a height that is an integer multiple of the height of the modular optical component retainer (e.g., two time as high), to facilitate the straightforward construction of optical modules from a mix of optical component and splice modular retainers. The side structures of the modular retainer may be positioned on the base and sized to be of equal height to the upward projecting finger pairs so that overall profile of the retainer is approximately the same size as the optical component or mass fusion splice.
The present invention provides many desirable advantages, features and benefits. The grid of complementary finger pairs creates a retention platform that provides great flexibility in laying out and building up optical modules. The snap-fit retention of the optical components and splices in the modular retainer affords precise registration of the elements with the desired spatial orientation without the use of an additional cover. The optical components may simply be pressed into place in the modular retainer by hand with low force and without any specials tools, or may be populated using conventional component insertion machines (such as pick and place machines). The slightly concave shape and resilient construction of the fingers further provides secure retention of the optical component or splice and enhanced physical protection of those elements which is augmented by the projection of the side structures to a height that is co-extensive with that of the upwardly projected finger pairs.
The interconnection feature of the invention allows any number of modular retainers to be simply and quickly snapped together, with low insertion forces and without specials tools, along their edges to form a structurally rigid planar array, or stacked top to bottom in a columnar array, or configured in a mixed planar and columnar matrix. The common footprint for all modular retainers advantageously allows mass fusion splices to be conveniently interspersed within the modular retainer matrix as necessary to realize the desired optical circuit.